I have added basic mircryption support (no cbc or key exchange) to my uiq irc client: http://quirc.rtfm.se 
It's a client meant for uiq smartphones (symbian phones with touch screen) but its written in personal java, which is essentially just regular old 1.1 java with awt. It isn't j2me, but the source could probably be used to mircryption-enable existing j2me clients without too much trouble (it doesn't depend on any j2se java cryptography classes).
In case you've never heard of symbian and/uiq, here are the phones running uiq: http://www.uiq.se/uiqphones
It's a client meant for uiq smartphones (symbian phones with touch screen) but its written in personal java, which is essentially just regular old 1.1 java with awt. It isn't j2me, but the source could probably be used to mircryption-enable existing j2me clients without too much trouble (it doesn't depend on any j2se java cryptography classes).
In case you've never heard of symbian and/uiq, here are the phones running uiq: http://www.uiq.se/uiqphones
